I am using the sample application available with IdentityServer4 : Quickstart6_AspNetIdentity.sln Using the ro.client, I am able to get the token.
But when I am using the same token to get the userinfo, I am getting 403 Forbidden error in the same sample. Using the sample as it is. Don't know if it is a bug or I am missing something in the parameters. Following all the parameters as mentioned in the document: https://identityserver4.readthedocs.io/en/release/endpoints/userinfo.html
Was missing the scope=openid while generating the token. It works fine now.